Image Registration plays very crucial role in case of medical imaging to register different modalities of images like CT (Computed Tomography) and PET (Positron Emission Tomography) registration. CT is essential for structural information of anatomic and PET (Positron Emission Tomography) is for functional information. Basically it is the procedure of transforming dissimilar sets of data into one coordinate system. These sets of data can be acquired from multiple image modalities, different viewpoints, similar or dissimilar sensors. MI based image registration has been found to be reasonably useful methods of image registration. However, it is found to be quite computationally intensive and time consuming process for enormous size images an...